"I know more than I can express in words, and the little I can express would not have been expressed, had I not known more."

At first this immediately suggested to me Lovelace's I could not love thee, dear, so much/Loved I not honour more, which I'd always thought of as a curious and odd thought, the reasoning of which I found difficult to follow. Reading the various clear explanations offered, it now seems to me the equivalent of Browning's simpler A man's reach must exceed his grasp, or what's a heaven for?

 

CHW